What is sleep myoclonus? But what is body twitching exactly? The scientific name for this phenomenon
is sleep myoclonus (also known as hypnic myoclonus), and happens when you shift from one sleep phase
into another. During these sleep transitions, the body muscles can have spasms called hypnagogic jerks
(or hypnic jerks), and are more likely to happen when you’re falling asleep, or during the light
stage of sleep that follows this first moment in the sleep cycle. The scientific name for this pretty
common phenomenon is hypnic myoclonus. (Getty Stock Images) Why does it happen? According to sleep
disorders specialist Reena Mehra, MD, MS, there are several possible explanations as to why sleep
myoclonus is pretty common. The most plausible theory is that the body misinterprets the light sleep
phase as wakefulness while also recognising that the muscles aren’t moving. The brain then sends a message
to the muscles to check in they’re still working so to keep then active as a way to protect the body.
The neurotransmitters released carry the message from your nerve cells, attaching to your muscle protein cells.
This attachment signals the cells to act in a certain way, causing your muscles to move